East To Fit. Strong Black Coated Steel. Various Sizes AvailableDimensions: F6: 6″ Diameter F76: 8″ Diameter F461: 10″ Diameter F2: 12″ Diameter F3: 15″ Diameter F4: 18″ Diameter. All of our loudspeaker grilles are made from black enamelled steel with a rubber surround. They are a strong and effective way of protecting loudspeakers. They can be clamped in place with speaker mounting clamps- Our Codes: F56- F22 & F23